Director Mani Ratnam shot the film in the misty valleys of Ooty to give it a soft, poetic atmosphere. Filming would start early in the dawn, around 5 AM, and wrap up by about 11 AM, in order to capture the scenes in a dreamy atmosphere; the cast and crew had to arrive on location one hour before filming. In addition, an ice machine was brought from Madras to provide any additional mist if the shot didn't look romantic enough.
In 1989, an 11-year old Delhi girl named Geethanjali was suffering from terminal cancer and wrote her thoughts and emotions in a diary, which was published around that time. Mani Ratnam was moved when he read the diary, and named his film, and the title heroine, after the little girl.
The film was shot in 60 days.
London-born Girija Shettar was a guest at Mani Ratnam's marriage to Suhasini, and was selected for the title role. She took two months to prepare for the role under associate director 'Gadiraju Keshava Rao'.